Batch fabricated scanning near field optical microscope/atomic force microscopy microprobe integrated with piezoresistive cantilever beam with highly reproducible focused ion beam micromachined aperture

Abstract

In scanning near field optical microscope (SNOM), an optical probe with aperture diameter well below the optical wavelength is moved over the sample. The sample-probe distance control is one of the key problems in SNOM. Our earlier approach allowed for fabrication of the piezo-SNOM/atomic force microscopy (AFM) probe, however, reproductivity of the process and optical quality of the device were not satisfactory. Now we report an innovative processing sequence, which offers highly reproductive batch processing, typical for semiconductor technology and renders it possible to produce cantilevers playing role of an AFM detector as well as a nanoaperture detector. Moreover, illumination of the aperture is easier because of a wide input opening and its big cone angle. The throughput is in the range of 10−5 and higher. Apertures in hollow pyramids have been formed by direct ion beam drilling with a focused beam of 30 keV Ga+ ions. Direct focused ion beam (FIB) drilling is a reproducible process for hole formation at the 30–100 nm diameter range. Formation of smaller apertures is possible if a special FIB drilling/deposition procedure is applied.